Efeito da dopagem com elementos de transição nas propriedades estruturais e ópticas do composto Ce2(MoO4)3

Abstract

Due to their promising properties in various fields of knowledge, molybdate-based materials, especially cerium molybdate Ce₂(MoO₄)₃, have been attracting considerable attention in the field of nanotechnology. Thus, the present work aimed at the synthesis and study of the cerium molybdate semiconductor Ce₂(MoO₄)₃ in both pure and transition metal-doped forms, to observe the influence of dopants on the physical and optical properties of the synthesized nanomaterials. For this purpose, the nanomaterials Ce1.8A0.2(MoO4)3 (A = Ag+1, Zn+2, Y+3, Ti+4, Nb+5) were synthesized using the microwave-assisted hydrothermal method and characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FEG-SEM), UV-vis spectroscopy, and photoluminescence spectroscopy. The diffraction patterns confirmed the formation of pure Ce₂(MoO₄)₃ without secondary phases. For the doped materials, the successful incorporation of the respective dopant atoms into the crystalline structure was observed. The FEG-SEM images revealed the influence of the dopant ion on the final morphology of the materials, showing changes from a nanoplate-like morphology to an oval, football-like shape. Additionally, variations in the band gap energy of the doped materials compared to pure Ce₂(MoO₄)₃ were observed, indicating the creation of intermediate levels between the valence band and the conduction band due to the insertion of dopant ions into the Ce₂(MoO₄)₃ structure. The photoluminescence spectra demonstrated a reduction in photoluminescence intensity and a broadening of the emission band within the visible spectrum, possibly due to a decrease in the electron-hole recombination rate. The broadening in the visible spectrum, along with CIE data and quality tests, confirmed that the doped materials are promising for high-quality cool white light emission for commercial environments. The samples Ce1,8Zn0,2(MoO4)3, Ce1,8Y0,2(MoO4)3 and Ce1,8Ti0,2(MoO4)3 exhibited x and y coordinates close to 0.33, CCT above 6000K, CRI greater than 96, and color purity lower than 7.12%. Based on these results, it is concluded that the microwave-assisted hydrothermal synthesis method was efficient for obtaining the nanomaterials Ce1.8A0.2(MoO4)3 (A = Ag+1, Zn+2, Y+3, Ti+4, Nb+5) and that the photoluminescent properties of the doped nanomaterials present potential applications for the fabrication of WLEDs (white light-emitting diodes) due to their white light emission.